// SPDX-License-Identifier: GPL-2.0

  /*
   * Driver for the RTC in Marvell SoCs.

   */
  
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/rtc.h>
  #include <linux/bcd.h>

  #include <linux/bitops.h>

  #include <linux/io.h>
  #include <linux/platform_device.h>

  #include <linux/of.h>

  #include <linux/delay.h>

  #include <linux/clk.h>

  #include <linux/gfp.h>

  #include <linux/module.h>

  
  
  #define RTC_TIME_REG_OFFS	0
  #define RTC_SECONDS_OFFS	0
  #define RTC_MINUTES_OFFS	8
  #define RTC_HOURS_OFFS		16
  #define RTC_WDAY_OFFS		24

  #define RTC_HOURS_12H_MODE	BIT(22) /* 12 hour mode */

  
  #define RTC_DATE_REG_OFFS	4
  #define RTC_MDAY_OFFS		0
  #define RTC_MONTH_OFFS		8
  #define RTC_YEAR_OFFS		16

  #define RTC_ALARM_TIME_REG_OFFS	8
  #define RTC_ALARM_DATE_REG_OFFS	0xc

  #define RTC_ALARM_VALID		BIT(7)

  
  #define RTC_ALARM_INTERRUPT_MASK_REG_OFFS	0x10
  #define RTC_ALARM_INTERRUPT_CASUE_REG_OFFS	0x14

  
  struct rtc_plat_data {
  	struct rtc_device *rtc;
  	void __iomem *ioaddr;

  	int		irq;

  	struct clk	*clk;

  };
  
  static int mv_rtc_set_time(struct device *dev, struct rtc_time *tm)
  {
  	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
  	void __iomem *ioaddr = pdata->ioaddr;
  	u32	rtc_reg;
  
  	rtc_reg = (bin2bcd(tm->tm_sec) << RTC_SECONDS_OFFS) |
  		(bin2bcd(tm->tm_min) << RTC_MINUTES_OFFS) |
  		(bin2bcd(tm->tm_hour) << RTC_HOURS_OFFS) |
  		(bin2bcd(tm->tm_wday) << RTC_WDAY_OFFS);
  	writel(rtc_reg, ioaddr + RTC_TIME_REG_OFFS);
  
  	rtc_reg = (bin2bcd(tm->tm_mday) << RTC_MDAY_OFFS) |
  		(bin2bcd(tm->tm_mon + 1) << RTC_MONTH_OFFS) |

  		(bin2bcd(tm->tm_year - 100) << RTC_YEAR_OFFS);

  	writel(rtc_reg, ioaddr + RTC_DATE_REG_OFFS);
  
  	return 0;
  }
  
  static int mv_rtc_read_time(struct device *dev, struct rtc_time *tm)
  {
  	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
  	void __iomem *ioaddr = pdata->ioaddr;
  	u32	rtc_time, rtc_date;
  	unsigned int year, month, day, hour, minute, second, wday;
  
  	rtc_time = readl(ioaddr + RTC_TIME_REG_OFFS);
  	rtc_date = readl(ioaddr + RTC_DATE_REG_OFFS);
  
  	second = rtc_time & 0x7f;
  	minute = (rtc_time >> RTC_MINUTES_OFFS) & 0x7f;

  	hour = (rtc_time >> RTC_HOURS_OFFS) & 0x3f; /* assume 24 hour mode */

  	wday = (rtc_time >> RTC_WDAY_OFFS) & 0x7;
  
  	day = rtc_date & 0x3f;
  	month = (rtc_date >> RTC_MONTH_OFFS) & 0x3f;
  	year = (rtc_date >> RTC_YEAR_OFFS) & 0xff;
  
  	tm->tm_sec = bcd2bin(second);
  	tm->tm_min = bcd2bin(minute);
  	tm->tm_hour = bcd2bin(hour);
  	tm->tm_mday = bcd2bin(day);
  	tm->tm_wday = bcd2bin(wday);
  	tm->tm_mon = bcd2bin(month) - 1;
  	/* hw counts from year 2000, but tm_year is relative to 1900 */
  	tm->tm_year = bcd2bin(year) + 100;

  	return 0;

  }

  static int mv_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
  {
  	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
  	void __iomem *ioaddr = pdata->ioaddr;
  	u32	rtc_time, rtc_date;
  	unsigned int year, month, day, hour, minute, second, wday;
  
  	rtc_time = readl(ioaddr + RTC_ALARM_TIME_REG_OFFS);
  	rtc_date = readl(ioaddr + RTC_ALARM_DATE_REG_OFFS);
  
  	second = rtc_time & 0x7f;
  	minute = (rtc_time >> RTC_MINUTES_OFFS) & 0x7f;

  	hour = (rtc_time >> RTC_HOURS_OFFS) & 0x3f; /* assume 24 hour mode */

  	wday = (rtc_time >> RTC_WDAY_OFFS) & 0x7;
  
  	day = rtc_date & 0x3f;
  	month = (rtc_date >> RTC_MONTH_OFFS) & 0x3f;
  	year = (rtc_date >> RTC_YEAR_OFFS) & 0xff;
  
  	alm->time.tm_sec = bcd2bin(second);
  	alm->time.tm_min = bcd2bin(minute);
  	alm->time.tm_hour = bcd2bin(hour);
  	alm->time.tm_mday = bcd2bin(day);
  	alm->time.tm_wday = bcd2bin(wday);
  	alm->time.tm_mon = bcd2bin(month) - 1;
  	/* hw counts from year 2000, but tm_year is relative to 1900 */
  	alm->time.tm_year = bcd2bin(year) + 100;

  	alm->enabled = !!readl(ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);

  
  	return rtc_valid_tm(&alm->time);

  }
  
  static int mv_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
  {
  	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
  	void __iomem *ioaddr = pdata->ioaddr;
  	u32 rtc_reg = 0;
  
  	if (alm->time.tm_sec >= 0)
  		rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_sec))
  			<< RTC_SECONDS_OFFS;
  	if (alm->time.tm_min >= 0)
  		rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_min))
  			<< RTC_MINUTES_OFFS;
  	if (alm->time.tm_hour >= 0)
  		rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_hour))
  			<< RTC_HOURS_OFFS;
  
  	writel(rtc_reg, ioaddr + RTC_ALARM_TIME_REG_OFFS);
  
  	if (alm->time.tm_mday >= 0)
  		rtc_reg = (RTC_ALARM_VALID | bin2bcd(alm->time.tm_mday))
  			<< RTC_MDAY_OFFS;
  	else
  		rtc_reg = 0;
  
  	if (alm->time.tm_mon >= 0)
  		rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_mon + 1))
  			<< RTC_MONTH_OFFS;
  
  	if (alm->time.tm_year >= 0)

  		rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_year - 100))

  			<< RTC_YEAR_OFFS;
  
  	writel(rtc_reg, ioaddr + RTC_ALARM_DATE_REG_OFFS);
  	writel(0, ioaddr + RTC_ALARM_INTERRUPT_CASUE_REG_OFFS);
  	writel(alm->enabled ? 1 : 0,
  	       ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
  
  	return 0;
  }

  static int mv_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)

  {

  	struct rtc_plat_data *pdata = dev_get_drvdata(dev);

  	void __iomem *ioaddr = pdata->ioaddr;
  
  	if (pdata->irq < 0)

  		return -EINVAL; /* fall back into rtc-dev's emulation */
  
  	if (enabled)

  		writel(1, ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);

  	else
  		writel(0, ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);

  	return 0;
  }
  
  static irqreturn_t mv_rtc_interrupt(int irq, void *data)
  {
  	struct rtc_plat_data *pdata = data;
  	void __iomem *ioaddr = pdata->ioaddr;
  
  	/* alarm irq? */
  	if (!readl(ioaddr + RTC_ALARM_INTERRUPT_CASUE_REG_OFFS))
  		return IRQ_NONE;
  
  	/* clear interrupt */
  	writel(0, ioaddr + RTC_ALARM_INTERRUPT_CASUE_REG_OFFS);
  	rtc_update_irq(pdata->rtc, 1, RTC_IRQF | RTC_AF);
  	return IRQ_HANDLED;
  }

  static const struct rtc_class_ops mv_rtc_ops = {
  	.read_time	= mv_rtc_read_time,
  	.set_time	= mv_rtc_set_time,
  };

  static const struct rtc_class_ops mv_rtc_alarm_ops = {
  	.read_time	= mv_rtc_read_time,
  	.set_time	= mv_rtc_set_time,
  	.read_alarm	= mv_rtc_read_alarm,
  	.set_alarm	= mv_rtc_set_alarm,

  	.alarm_irq_enable = mv_rtc_alarm_irq_enable,

  };

  static int __init mv_rtc_probe(struct platform_device *pdev)

  {

  	struct rtc_plat_data *pdata;

  	u32 rtc_time;

  	int ret = 0;

  	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
  	if (!pdata)
  		return -ENOMEM;

  	pdata->ioaddr = devm_platform_ioremap_resource(pdev, 0);

  	if (IS_ERR(pdata->ioaddr))
  		return PTR_ERR(pdata->ioaddr);

  	pdata->clk = devm_clk_get(&pdev->dev, NULL);
  	/* Not all SoCs require a clock.*/
  	if (!IS_ERR(pdata->clk))
  		clk_prepare_enable(pdata->clk);

  	/* make sure the 24 hour mode is enabled */

  	rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
  	if (rtc_time & RTC_HOURS_12H_MODE) {

  		dev_err(&pdev->dev, "12 Hour mode is enabled but not supported.
  ");

  		ret = -EINVAL;
  		goto out;

  	}

  	/* make sure it is actually functional */
  	if (rtc_time == 0x01000000) {
  		ssleep(1);
  		rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
  		if (rtc_time == 0x01000000) {
  			dev_err(&pdev->dev, "internal RTC not ticking
  ");

  			ret = -ENODEV;
  			goto out;

  		}
  	}

  	pdata->irq = platform_get_irq(pdev, 0);

  	platform_set_drvdata(pdev, pdata);

  	pdata->rtc = devm_rtc_allocate_device(&pdev->dev);

  	if (IS_ERR(pdata->rtc)) {
  		ret = PTR_ERR(pdata->rtc);
  		goto out;
  	}

  	if (pdata->irq >= 0) {
  		writel(0, pdata->ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
  		if (devm_request_irq(&pdev->dev, pdata->irq, mv_rtc_interrupt,

  				     IRQF_SHARED,

  				     pdev->name, pdata) < 0) {
  			dev_warn(&pdev->dev, "interrupt not available.
  ");
  			pdata->irq = -1;
  		}
  	}

  	if (pdata->irq >= 0) {
  		device_init_wakeup(&pdev->dev, 1);
  		pdata->rtc->ops = &mv_rtc_alarm_ops;
  	} else {
  		pdata->rtc->ops = &mv_rtc_ops;
  	}

  	pdata->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
  	pdata->rtc->range_max = RTC_TIMESTAMP_END_2099;

  	ret = rtc_register_device(pdata->rtc);
  	if (!ret)
  		return 0;

  out:
  	if (!IS_ERR(pdata->clk))
  		clk_disable_unprepare(pdata->clk);
  
  	return ret;

  }
  
  static int __exit mv_rtc_remove(struct platform_device *pdev)
  {
  	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

  	if (pdata->irq >= 0)
  		device_init_wakeup(&pdev->dev, 0);

  	if (!IS_ERR(pdata->clk))
  		clk_disable_unprepare(pdata->clk);

  	return 0;
  }

  #ifdef CONFIG_OF

  static const struct of_device_id rtc_mv_of_match_table[] = {

  	{ .compatible = "marvell,orion-rtc", },

  	{}
  };

  MODULE_DEVICE_TABLE(of, rtc_mv_of_match_table);

  #endif

  static struct platform_driver mv_rtc_driver = {
  	.remove		= __exit_p(mv_rtc_remove),
  	.driver		= {
  		.name	= "rtc-mv",

  		.of_match_table = of_match_ptr(rtc_mv_of_match_table),

  	},
  };

  module_platform_driver_probe(mv_rtc_driver, mv_rtc_probe);

  
  MODULE_AUTHOR("Saeed Bishara <saeed@marvell.com>");
  MODULE_DESCRIPTION("Marvell RTC driver");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:rtc-mv");